Preparation of triazinyl-bis-anthraquinone dyes by reacting aryldihalotriazine with amino anthraquinone

ABSTRACT

Anthraquinone dyes I ##STR1## (Ar = aryl, A = anthraquinonyl) are prepared by reacting a aryldihalotriazine II ##STR2## (Hal = chlorine or bromine) with an aminoanthraquinone III 
     
         A--NH.sub.2 
    
     in an N--C 1  --C 4  -alkylpyrrolid-2-one or -piperid-2-one, N-di-C 1  -C 4  -alkylacetamide or -propionamide or urea derivatives of the formula IV ##STR3## (R = identical or different alkyl groups of from 1 to 4 carbon atoms which can also be linked together to form a 5- or 6-membered ring containing the urea group) as solvent.

The present invention relates to an improved process for preparinganthraquinone dyes of the general formula I ##STR4## where Ar is aryland the A radicals are each anthraquinonyl radicals, by reacting anaryldihalotriazine of the general formula II ##STR5## where Hal ischlorine or bromine, with an aminoanthraquinone III

    A--NH.sub.2 III

in an organic solvent.

Anthraquinone dyes of the formula I belong to the important group of thevat dyes.

As is already known from DE patents 551,884, 637,937 and 1,026,456, thedyes I are obtainable by reacting the aryldichlorotriazines II with theamino-anthraquinones III in a high-boiling aromatic solvent such asnitrobenzene or di- or trichlorobenzene. However, the yields of from 85to 90% obtainable with this process are unsatisfactory.

Attempts to improve the process by including bases and a copper(I)aminecatalyst (DE patent 1,795,102) had only limited success and in the caseof the particularly important dye Vat Blue 66 (Ar = phenyl, A=1-amino-2-acetylanthraquinon-4-yl) led even to a yield of only 53%.

It is an object of the present invention to make available the dyes I inbetter yields and in a more economical manner.

We have found that this object is achieved by a process for preparing ananthraquinone dye of the general formula I ##STR6## where Ar is aryl andthe A radicals are each anthraquinonyl, by reacting anaryldihalotriazine of the general formula II ##STR7## where Hal ischlorine or bromine, with an aminoanthraquinone III

    A--NH.sub.2                                                III

in an organic solvent, which comprises using as solvent for this purposean N--C₁ -C₄ -alkylpyrrolid-2-one, N--C₁ -C₄ -alkylpiperid-2-one, N-di-C-C -alkylacetamide or N-di-C₁ -C₄ -alkylpropionamide or a ureaderivative of the formula IV ##STR8## where the radicals R are identicalor different alkyl groups of from 1 to 4 carbon atoms which can also belinked to one another to form a 5- or 6-membered ring containing theurea group.

Suitable solvents for the purposes of the present invention are

N-C₁ -C₄ -alkylpyrrolid-2-ones such as N-ethyl-, N-n-propyl-,N-isopropyl- or N-n-butyl-pyrrolidone, preferably N-methylpyrrolidone,

N-C₁ C₄ -alkylpiperid-2-ones, such as N-ethyl-, N-n-propyl-,N-isopropyl- or N-n-butylpiperidone, preferably N-methylpiperidone,

urea derivatives of the formula IV with 4 identical or different C₁ -C₄-alkyl groups as radicals R such as tetra-n-propyl-, tetra-n-butyl- ordimethyldiethyl-urea, preferably tetramethyl- or tetraethyl-urea, orwith radicals R which link together as ethyleneor propylene-ureas toform a 5- or 6-membered ring containing the urea group, such as1,3-diethyl- or 1,3-dipropyl-imidazolidin-2-one or 1,3-diethyl- or1,3-dipropyl-tetrahydro-2(lH)-pyrimidinone, preferably1,3-dimethylimidazolidin-2-one or1,3-dimethyl-tetrahydro-2(1H)-pyrimidinone, and

N-di-C₁ -C₄ -alkyl-acetamides or -propionamides such as diethyl-,di-n-propyl- or di-n-butyl-acetamide or dimethyl-, diethyl-,di-n-propyl- or di-n-butylpropionamide, preferably dimethylacetamide.

These solvents are very potent solvents for the starting materials ofthe process. Thus, the amount of solvent is in general only 2-6,preferably 2.5-4 kg per kg of III.

The reaction can also be carried out in the presence of acid-bindingagents such as the alkali metal salts of weak acids, for example sodiumacetate, sodium carbonate or potassium carbonate.

Furthermore, it is also possible to use a catalyst in the form of anaddition compound of copper(I) iodide or bromide with a tertiary basesuch as triethylamine, pyridine or related compounds.

The starting compounds II an III are known or obtainable by knownmethods. The molar ratio of II to III is advantageously from 0.5:1 to1:1, in particular from 0.6:1 to 0.8:1.

In general, the reaction is carried out at from 80 to 200° C.,preferably at from 100 to 160° C. The reactants can be addedalternatively before or after the reaction temperature has been reached.It is also possible to increase the temperature during the reaction inorder to achieve complete conversion.

The reaction is in general carried out under atmospheric pressure butcan also be carried out under reduced pressure.

The reaction times including the after-stirring times are in generalfrom 5 to 12, preferably from 6 to 8, hours.

The reaction mixture is worked up for the products in a conventionalmanner, preferably by cooling the solution and separating off theprecipitating dyes I and washing them or by distilling the solvent outof the reaction mixture.

The dyes I are obtained in very high purity and distinctly better yieldthan heretofore.

Since the solvent, after separation from the dyes I, is obtained in awater-free or at least low-water form and thus is readily regenerable,moreover, water pollution is kept to a minimum.

The process of the present invention is of particular importance forthose dyes I where Ar is for example chlorophenyl, dichlorophenyl,bromophenyl, tolyl, methoxyphenyl, ethoxyphenyl or dimethylaminophenyl,preferably phenyl, and which are derived from the followingaminoanthraquinones III:

1,4-, 1,5-, 1,8- or 2,6-diaminoanthraquinones,

1-amino-4-alkoxyanthraquinones, preferably1-amino-4-methoxyanthraquinone,

1-amino-4-(or 5)-aroylaminoanthraquinones or chlorine, bromine ormethoxy derivatives thereof, preferably1-amino-5-benzoylaminoanthraquinone,

preferably from 1- or 2-aminoanthraquinones or chlorine or brominederivatives thereof,

particularly preferably from 1,4-diamino-2-acetyl-anthraquinone.

A particularly preferred application of this process is the preparationof the abovementioned Vat Blue 66 dye.

EXAMPLES

Preparation of dyes of the formula ##STR9##

A solution of a mol of an aminoanthraquinone III and b g of a solvent Swas admixed at T₁ ° C. with 0.18 mol of2-phenyl-4,6-dichloro-1,3,5-triazine (II) in the course of 45 min,maintained at T₁ ° C. for t₁ hours and, following a heating-up time of 2h, subsequently stirred at T₂ ° C. for t₂ hours.

Then the solution was cooled down to 60-70° C., the dye I forming aprecipitate. The precipitate was separated off, washed initially withsolvent S and then with water and thereafter dried.

The details of these experiments and the results thereof are summarizedin the following table:

                                      TABLE                                       __________________________________________________________________________                   a              b  T.sub.1                                                                          t.sub.1                                                                         T.sub.2                                                                          t.sub.2                                                                          Yield                             Example                                                                            Anthraquinone III                                                                       mol                                                                              Solvent S   g  °C.                                                                       h °C.                                                                       h  of I                              __________________________________________________________________________    1    1,4-diamino-2-acetyl                                                                    0.27                                                                             N-methylpyrrolid-2-one                                                                    250                                                                              120                                                                              2.5                                                                             150                                                                              2  98%                               2    1,4-diamino-2-acetyl                                                                    0.27                                                                             N-methylpyrrolid-2-one                                                                    190                                                                              120                                                                              2.5                                                                             150                                                                              2  98%                               3    1,4-diamino-2-acetyl                                                                    0.27                                                                             N-methylpyrrolid-2-one                                                                    375                                                                              120                                                                              2.5                                                                             150                                                                              2  98%                               4    1,4-diamino-2-acetyl                                                                    0.27                                                                             N-methylpyrrolid-2-one                                                                    250                                                                              100                                                                              3 150                                                                              2  98%                               5    1,4-diamino-2-acetyl                                                                    0.27                                                                             N-methylpyrrolid-2-one                                                                    250                                                                              130                                                                              --                                                                              130                                                                              4-5                                                                              98%                               6    1,4-diamino-2-acetyl                                                                    0.27                                                                             N-methylpyrrolid-2-one                                                                    250                                                                              160                                                                              --                                                                              160                                                                              4-5                                                                              98%                               7    1,4-diamino-2-acetyl                                                                    0.27                                                                             1,3-dimethyl-                                                                             250                                                                              120                                                                              2.5                                                                             150                                                                              2  94%                                                 imidazolid-2-one                                            8    1,4-diamino-2-acetyl                                                                    0.27                                                                             1,3-dimethyltetrahydro-                                                                   250                                                                              120                                                                              2.5                                                                             150                                                                              2  92%                                                 2(1H)-pyrimidin-2-one                                       9    1,4-diamino-2-acetyl                                                                    0.27                                                                             tetramethylurea                                                                           250                                                                              120                                                                              2.5                                                                             150                                                                              2  92%                               10   1-amino   0.24                                                                             N-methylpyrrolid-2-one                                                                    250                                                                              120                                                                              2.5                                                                             150                                                                              2  72%                               11   2-amino   0.24                                                                             N-methylpyrrolid-2-one                                                                    250                                                                              120                                                                              2.5                                                                             150                                                                              2  92%                               __________________________________________________________________________

We claim:
 1. A process for preparing an anthrquinone dye of the formula##STR10## where Ar is aryl and the A radicals are each anthraquinonyl,by reacting an aryldihalotriazine of the formula ##STR11## where Hal ischlorine or bromine, with an aminoanthraquinone of the formula

    A--NH.sub.2                                                [III]

in an organic solvent selected from the group consisting of N-C₁ -C₄-alkylpyrrolid-2-one, N-C₁ -C₄ -alkylpiperid-2-one, N-di-C₁ -C₄-alkylacetamide, N-di-C₁ -C₄ -alkylpropionamide, a urea derivative ofthe formula ##STR12## where the radicals R are identical or differentalkyl groups of from 1 to 4 carbon atoms, 1,3-di-(C₁ -C₄-alkyl)-imidazolidin-2-one and 1,3-di-(C₁ -C₄-alkyl)-tetrahydro-2(1H)-pyrimidinone.
 2. A process as claimed in claim1, wherein the organic solvent used is N-methylpyrrolidone,tetramethylurea, tetrathylurea, 1,3-dimethylimidazolidin-2-one,1,3-dimethyltetrahydro-2(1H)-pyrimidinone or dimethylacetamide.
 3. Aprocess as claimed in claim 1 or 2, wherein Ar is phenyl and A is1-amino-2-acetylanthraquinon-4yl.
 4. A process as claimed in claim 1 or2 or 3, wherein the reaction is carried out at from 80 to 180° C.